On-board electrical subsystems having similar voltage levels are often interconnected but have voltage differences in real operation due to the different storage device technologies or storage device states of charge. In the case of 12 V on-board electrical systems with lead-acid batteries and lithium-ion batteries, voltage differences of up to 4 V can occur. A further problem may arise if on-board electrical system consumers in one on-board electrical subsystem require a high stability of the supply voltage, whereas the consumers in the other on-board electrical subsystem are highly dynamic. Switching elements are therefore known in on-board electrical systems of this type with on-board electrical subsystems for connecting or disconnecting the on-board electrical subsystems in a targeted manner.
In principle, the control strategy can be calculated by a microprocessor of a control device and a corresponding driver circuit can then be controlled for the transistors. However, this is critical in terms of the regulating speed. Alternatively, at least a part of the control unit can be designed in hardware, which is faster, but also incurs higher costs.
Disclosed embodiments provide a device for disconnecting and connecting on-board electrical systems, offering high regulating speed but incurring lower costs. Disclosed embodiments also provide a suitable method for the disconnection and connection.